Comminutor



Feb. 29, 1944. A. c. DURDIN, JR

COMMINUTORS Filed March 7, 1940 INVENTOR. I

ATTORNEYS,

Patented Feb. 29, 1944 's PATENT.

FFICE'T COMMINUTOR Augustus o. Durdin, In, Chicago, 111. ApplicationMarch i, 1940', Serial No. 322,639

9 Claims. (01. 210-152) This invention relates to comminutors andparticularly to comminutors of the rotary screen type which are employed for comminuting solids carried by liquids such as is the case in'sewage. comminutors intended to comminute solids carried by liquids normally comprise a screen through which the liquid passes. The solids are retained by the screen and they are subjected to comminution by devices of various kinds. In one well known form of comminutors a rotary screen is employed, the liquid passing'from the exterior into the interior of the screen, from whence itv flows to. a suitable outlet channel. The rotary screen is normally provided with teeth which cause retained solids to mov with the screen. These teeth cooperate with suitable stationary cutting mechanism to effect comminution of the solids.

A problem arises with comminutors of this type from the fact that solids carried by liquid for the most parteither sink or float, since it is only occasionally that solid material has exactly the same specific gravity as the water which carries the solids.

One of the principal objects of the present invention is to provide an improved comminutor in which the liquid is caused to pass around a screen with a whirling or rotating movement relative to its direction of flow. The rotating movement or whirling of the stream causes all the solids therein, both the normally floating solids and the normally sunk solids, to perform orbits within the floating stream. Since the stream is draining through the screen, the-solids are presented to the screen at various levels, ranging from water level down to the" bottom of the screen. These solids are'held against the screen by water pressure and are transferred to cutting mechanism, where they are'co'mminuted. Consequently the cutting operation is dis-- tributed through the whole submerged depth of the screen and therefore no excessive wear occurs from normally floating solids at the water level and from normally sunk solids at the bottom of the screen. I

A further objector the invention is to provide a comminutor in which the incoming stream of liquid and the movement of the stream combine to create a whirlpool which is adapted to return solids from which pieces have been cut back to the stream for further presentation to the screen.

The invention will more readily be understood from the following description, taken in conjunction with the accompanying drawing, in which: Figure l is a per p c i e view, partly br lsen line 2--2 of Fig. 1, and

away, showing a comminutor and comminutor chamber equipped with means ,for imparting a rotary or whirling motion to the stream passing around the comminutor screen; a

Fig. .2 is a longitudinal sectional view of th device in Fig. 1, the section being taken on the Fig. 3 is a similar view showing my invention in a modified form.

Referring to the drawing, the reference numeral I0 indicates a concrete structure in which the comminutor is located. The incoming sewage enters by-the conduit II, from which it may be directed through a channel l2 to either one oiv two comminutors, only one of which is illustrated. The channels l2 are provided with guideways l3 for the reception of slide plates to direct the flow through only one. of the channels I2.

Each of the channels 12 leads into a comminutor chamber M, the outlet of which is a U- shaped conduit 15 extending fromthe bottom of the chamber M to an egress conduit 16.

The comminutor comprises a casting I'I upon which is rotatably mounted the screen l8. The screen l8 carries teeth I!) which are adapted to engage solid materials and'carry them into .811?

gagement with a stationary comb 20 which is mounted on the casting H. In passing through the comb the teeth l9 tear small pieces out of the solid objects, whichsmall pieces pass through the screen l8 into the egress channel It. Even; tually the complete solid object is comminuted into small pieces and passed into the egress stream.

The comminutor chamber I4 is substantially circular in plan and the "screen I8 is located in eccentric relation therein so that the liquid en tering through the channel I2 is presented with an initially wide path which gradually narrows around the screen. The casting I! comprises a vertical portion 2| which closes this path adjacent one side of the associated channel l2. The

casting I! also comprises a boss 22, upon which is mounted the motor 23 which drives the screen I8. The comminutor is maintained inposition by means of nuts 24 with its annular base 25 around the entrance of the eduction conduit l5.

The channel I2 enters the chamber [4 in substantially tangential relation thereto as is best seen in Figure 1.

Means are provided for imparting to the stream .invention previously described.

the channel 12. The structure 26 may suitably be formed of concrete and it may be'integral with the concrete structure providing the channel 12 and the chamber M. The cradle structure 28 provides an eifective bottom for the channel l2 which is of substantially semi-cylindrical form.

Upon the interior surface of the cradle structure 26 are provided a plurality of vanes 21 which are arranged in sharply helical formation. These vanes are preferably in the form of helices of very steep pitch. At their forward. ends, that. is, the ends adjacent the inlet end of the channel l2, the vanes 27 are tapered down to substantial disappearance, as shown at 28, so that they pre sent no sharp corners upon which rags or other debris might catch. The vanes 2 may suitably be formed integral with the cradle member 26,

although they may be of different material if desired. i

In the embodiment of the invention illustrated in Fig 3', the channel 1.2 is closed. ofli by two transverse partitions 30. Through these partitions extends a. cylindrical structure 29, which is preferably located very close to the bottom ofthe channel 12; The cylindrical structure 29 may suitably be of'metal. and it is provided with helical vanes 3| which are substantially similar to. the helical vanes2'l of the embodiment of the The helical blades 31 are tapered away at the inlet end of the cylindrical member 29' in thesame manner as the vanes?! are tapered at 28'.

The two embodiments of the invention de-.

scribed above differ principally in that the second embodiment provides a cylindrical surface having vanes, whereas the first embodiment has a substantially semi-cylindrical surface provided with" vanes. The vanes in both cases being arranged helically, impart to the liquid flowing around the comminutor screen 13 a whirling or rotary'movement. This whirling or rotary movement causes a similar movement of solid materials in the stream; that is, solid materials which are normally submerged and solid materials which. normally float are carried around by the whirling stream so that. they are presented to the screen l8 at various levels extending from the water level. down to the bottom of the screen. When the solid materials are engaged by the screen lil.,the water pressure tends to hold them in position and they are carried around so that they are. disintegrated by the teeth l9 and the comb in the manner described above.

The cutting operation is performed at the position of the. comb. 2B, which is. located within a recess; or. concavity 33 in the casting l1. This concavity is located alongside the point where the. channel 12 enters the chamber M. The flow of thestream entering from the channel l2 past the recessor concavity 33 and the movement of the screemwhich is opposite to that of the stream, engender a whirlpool in this recess or concavity. When. the solid: materials are disengaged from the screen; as a" result. of the cutting operation at the comb- 20, this whirlpool carries the disengaged solids outwardly into the incoming stream; which carries them around again for engagement with the screen 18 and the teeth IS in the manner described above. The whirling nature of" the incoming stream tends to maintain its-course independent of the liquid in the whirlpool: in the concavity the effect of the stream moving past the liquid in the whirlpool and. the opposite movement of the screen energize and accentuate the whirlpool movement of the liquid in the concavity 33.

Although the invention has been disclosed in connection with the specific details of preferred embodiments thereof, it must be understood that such details are not intended to be limitative of the invention except in so far as set forth in the accompanying claims.

Having thus described my invention, what'I claim as new and desire-to secureby Letters Patent of the United States. is:

1. In a comminutor comprising a rotary screen, means defining a path for a stream of liquid around the screen, an eduction passage within the screen, and means including vanes in said path and in. a generally helical relation to the direction of said path for imparting a whirling c-r rotary movement to said stream.

2.. In a comminutor comprising a rotary screen, means defining a path for a stream of liquid including a. liquid: supply conduit and; wall means substantially enclosing: thescreen: and in spaced relation, thereto, and means including vanes, located in said path, said vanes being in helical arrangement: to; the direction. of flow for impartinga whirling or rotary movement tosaid stream.

3. In a comminutor comprising. a rotary screen, means: defining a path for a stream of liquid around the. screen, an eduction passage within the screen anda conduit" for supplying said stream of liquid to said path, and vanes in said conduit arranged in helical relation to the longitudinal direction of said conduit. for imparting a whirling or rotary movement'to said stream.

4. A comminut-or comprising a. rotary screen, a chambcrreceiying said screen in eccentric relation, a. passageway enteringsaidchamber in tangential relation, means extending between said screen and the Wall of said chamber providing a substantial recess adjacent the. point of ent of said. passageway; cooperating cutting means on, saidscrecn; and last said'means; said passageway and the space between. the chamber and screen defining a path for liquid, meansv including vane members arranged in said path and in a substantially helical relation thereto, whereby a rotaryor whirling motion. is imparted to the liquid passing around they screen in said chamher,- and means for rotating said screen so as to carry solid materials into said recess Where portions are severed therefrom, whereby the stream entering by the, passageway and the movementof said screen are'adaptedz to create a Whirlpoolin said recess which is adapted to return. solid materials tosaid stream.

5. A comminutor comprising a rotary screen, a chamber receiving said screen in eccentric relation,. a passageway entering said chamber in tangential relation, means extending between said screen and the wall of said chamber providing a substantial recess adjacent the point of entry of said passageway, cooperating cutting means on said screen; and last said, means, Vane means in said passag w y and arranged, in a. substantially helical relation thereto for imparting a rotary or whirling motion to. liquid passing through. said passageway and around; the. screen in said, chamher, and means, for, rotating said screen so as to carry solid materials into said recess Where portions are severed; therefrom, whereby the stream entering by the passageway and the movement of said screen are adapted to create a whirlpool in said recess which is adapted to return solid materials to said stream.

6. A comminutor comprising a substantially circular chamber, a screen eccentrically arranged in said chamber, a passageway entering said chamber in substantially tangential relation so as to supply a stream of liquid to a gradually converging path around said screen, stationary means and means on said screen in cooperating cutting relation, means for rotating said screen to cause said cutting means to operate on solid materials, a cradle member in said passageway and vane members on said cradle in a substantially helical relation to the longitudinal direction of said passageway whereby the entering stream is caused to rotate or whirl around the general axis of the stream.

7. A comminutor comprising a substantially circular chamber, a screen eccentrically arranged in said chamber, a passageway entering said chamber in substantially tangential relation so as to supply a stream of liquid to a gradually converging path around said screen, stationary means and means on said screen in cooperating cutting relation, means for rotating said screen to cause said cutting means to operate on solid materials, means in said passageway defining an enclosed conduit and vane members in said conduit and in a substantially helical relation to the longitudinal direction of said conduit whereby the entering stream is caused to rotate or Whirl around the general axis of the stream.

8. A comminutor comprising a substantially circular chamber, a screen eccentrically arranged in said chamber, a passageway entering said chamber in substantially tangential relation so as to supply a stream of liquid to a gradually converging path around said screen, stationary means and means on said screen in cooperating cutting relation, a cradle member in said passageway, vane members on said cradle and arranged in a substantially helical relation to the longitudinal direction of said cradle whereby the entering stream is caused to rotate or whirl around the general axis of the stream, and means extending between said screen and the wall of the chamber adjacent the said passageway defining a recess, and means for rotating said screen in a direction opposite to said stream to cause said cutting means to operate on solid materials, whereby the incoming stream and the rotation of said screen engender a whirlpool in said recess.

9. A comminutor comprising a substantially circular chamber, a screen eccentrically arranged in said chamber, a passageway entering said chamber in substantially tangential relation so as to supply a stream of liquid to a gradually converging path around said screen, stationary means and means on said screen in cooperating cutting relation, means in said passageway defining a closed conduit, vane members in said conduit and arranged in a substantially helical relation to the longitudinal direction of said conduit whereby the entering stream is caused to rotate or whirl around the general axis of the stream, and means extending between said screen and the wall of the chamber adjacent the said passageway defining a recess, and means for rotating said screen in a direction opposite to said stream to cause said cutting means to operate on solid materials, whereby the incoming stream and the rotation of said screen engender a whirlpool in. said recess.

AUGUSTUS C. DURDIN, JR. 

